This invention relates generally to transition metal oxide-containing materials and, more particularly, to vanadium oxide-containing compositions and the rational synthesis thereof.
Transition metal oxide surfaces are known to serve as catalytic surfaces for a large number of important industrial chemical transformations. The mechanism of their interaction with substrate molecules, however, is generally not well understood due mainly to the complex nature of these poorly characterized surfaces that are generally inaccessible to various physical chemical analytical techniques. As a result, the suitability of particular catalytic surfaces for specific processes is currently commonly determined empirically with practically little or no possibility of systematic improvements in the performance of such catalytic materials.
As will be appreciated, numerous environmental and technological challenges exist for the application of such catalytic materials. Such challenges range from and include the removal of toxic materials from automotive vehicle exhaust and industrial flue streams, selective or controlled oxidation of hydrocarbons, photochemical conversion of water into H.sub.2 and O.sub.2, synthesis of gasoline from synthesis gas (also referred to as "syn-gas"), cost-effective nitrogen fixation, preparation of food stuffs and drugs, and removal of urea from blood, for example.
Polyoxometalates or transition metal oxide clusters (such as of vanadium, molybdenum and tungsten, for example) and their derivatives provide remarkably diverse and well-defined building blocks generally believed well suited for use in generating or assembling nanosized molecular systems. Recently, conventional organic and inorganic ligands (e.g., PO.sub.4.sup.3-, AsO.sub.4.sup.3-, SO.sub.4.sup.2-, etc.) have been used to join together or "glue" metal oxide moieties to prepare supramolecular structures and solids. Such ligands, however, generally have only limited thermal stability and may be scarce.
In view of the above, there is a need and a demand for a rational synthesis of well characterizable metal oxide surfaces with desired features--with and without immobilized catalytic active groups (such as metal ions, cluster compounds, organometallic fragments, asymmetric ligands, enzymes or cells, for example) such as may be helpful or useful in the satisfaction of one or more environmental or technological requirements such as described above.